LITTLE ROCK (AP) — A Democratic group on Friday began airing a television ad in Arkansas criticizing Republican Senate hopeful and U.S. Rep. Tom Cotton over the federal government shutdown, the latest volley in a high-dollar air war underway more than a year before Election Day.

Senate Majority PAC announced that it was spending about $100,000 to air the 30-second ad in Little Rock over the next week. It’s the second TV spot the group has run against Cotton, a first-term lawmaker who announced in August he was challenging Democratic Sen. Mark Pryor next year.

The ad criticizes Cotton for backing the push to tie the budget debate to efforts to defund the federal health care law, which has resulted in the standoff that’s left the federal government shut down since Oct. 1.

“Congressman Tom Cotton recklessly voted to shut down the government and threaten default,” the narrator says in the ad.

The spot is the latest in back-and-forth ads that have launched this week surrounding the race between Cotton and Pryor, who’s considered by Republicans to be the most vulnerable Arkansas incumbent seeking re-election this year.

Pryor on Thursday called on Cotton to pull down his first ad of the campaign, after PolitiFact.com, the fact-checking website of the Tampa Bay Times, said Cotton’s claim that Pryor supported a congressional exemption from the health care law was false.

The Club for Growth, a group backing Cotton’s bid, is also airing ads in Arkansas this week targeting Pryor.

Justin Brasell, Cotton’s campaign manager, criticized Pryor and Democrats over the new ad Friday and said that Cotton was focused on trying to reduce the national debt.

“What’s reckless and irresponsible is the big-spending agenda of Mark Pryor and Barack Obama,” Brasell said in an email.

Pryor was elected to the Senate in 2002 and re-elected in 2008. Cotton was elected in November to represent south Arkansas’ 4th Congressional District.